1. Field of the Invention:
This invention relates in general to a rotational position detecting apparatus for detecting angular and reference positions of the rotating shaft of an internal combustion engine. More particularly the invention provides to an apparatus of a simplified construction, compared with known apparatus, utilizing only a single rotation signal generating device and a single rotation signal detecting device.
2. Description of the Prior Art:
Heretofore various apparatus have been proposed for detecting angular and reference positions of an internal combustion engine. In one such apparatus, a plurality of teeth are indented around a circuilar disc rotating in synchronism with the rotating part of the engine or around the rotor of the engine. Teeth movement is detected by a sensor such as a photocoupler or an electromagnetic pick-up device. A second sensor is provided for detecting a reference position (for instance as in the model 5MGE-U engine made by Toyoya). Although the apparatus functions effectively, it is disadvantageous in that it is expensive to produce. In another known apparatus, disclosed in U.S. Pat. No. 4,181,884, the reference position is detected by a single sensor which detects a lost portion among the teeth. In still another known apparatus as disclosed, in U.S. Pat. Nos. 3,930,201 and 4,265,210, the rotation detecting device has been made of a digital circuit.